Conveyor systems having a number of individual carrying carts have been commonly used for many years to carry and sort packages or other items, such as mail. For example, U.S. Pat. No. 5,054,601 to Sjogren et al. discloses a package sorting conveyor comprised of a train of tilt tray carriers coupled in tandem to form a continuous loop. Each carrier includes a pivotally mounted tilt tray normally maintained in an upright position. The carriers are moved around the loop by a series of motors spaced around the loop. Branching out from the loop are outfeed chutes or the like for receiving packages from the carriers. When a particular carrier holding a particular package to be sorted reaches a selected outfeed chute, an actuator tilts the tray to dump the package into the outfeed chute. Another example of a typical package sorting conveyor is disclosed in International PCT Application Number PCT/DK90/00047 of Kosan Crisplant A/S, now U.S. Pat. No. 5,664,660.
It is also known in the art to use an electric motor for each supporting unit for causing the tilting movement of each load carrying platform. However, there are acceleration, deceleration and mechanical resistance challenges associated with electronically powering the tilt of each load carrying platform. Each tilt must occur precisely at the right moment; the electric motor must accommodate for a relatively heavy load during tilt; and the tray must be able to recover rapidly to a neutral position.
Additionally, it is difficult to track the tilt and position of each of the trays to ensure that each cart is properly functioning, positioned and prepared to repeatedly tilt, recover and deliver packages to the outfeed chutes without delay.
Thus, Applicant's a need for a sorting conveyor which includes individual conveyor carts having a new and improved tilting mechanism that is adapted for tilting the carrying tray while, at the same time, determining the direction of tilt of the tray.